Covalent Aurora A regulation by the metabolic integrator coenzyme A.

Aurora A kinase is a master mitotic regulator whose functions are controlled by several regulatory interactions and post-translational modifications. It is frequently dysregulated in cancer, making Aurora A inhibition a very attractive antitumor target. However, recently uncovered links between Aurora A, cellular metabolism and redox regulation are not well understood. In this study, we report a novel mechanism of Aurora A regulation in the cellular response to oxidative stress through CoAlation. A combination of biochemical, biophysical, crystallographic and cell biology approaches revealed a new and, to our knowledge, unique mode of Aurora A inhibition by CoA, involving selective binding of the ADP moiety of CoA to the ATP binding pocket and covalent modification of Cys290 in the activation loop by the thiol group of the pantetheine tail. We provide evidence that covalent CoA modification (CoAlation) of Aurora A is specific, and that it can be induced by oxidative stress in human cells. Oxidising agents, such as diamide, hydrogen peroxide and menadione were found to induce Thr 288 phosphorylation and DTT-dependent dimerization of Aurora A. Moreover, microinjection of CoA into fertilized mouse embryos disrupts bipolar spindle formation and the alignment of chromosomes, consistent with Aurora A inhibition. Altogether, our data reveal CoA as a new, rather selective, inhibitor of Aurora A, which locks this kinase in an inactive state via a "dual anchor" mechanism of inhibition that might also operate in cellular response to oxidative stress. Finally and most importantly, we believe that these novel findings provide a new rationale for developing effective and irreversible inhibitors of Aurora A, and perhaps other protein kinases containing appropriately conserved Cys residues.

Efficacy and tolerability of adding coenzyme A 400 U/d capsule to stable statin therapy for the treatment of patients with mixed dyslipidemia: an 8-week, multicenter, double-blind, randomized, placebo-controlled study.

BACKGROUND: Patients with mixed hyperlipidemia usually are in need of combination therapy to achieve low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) target values for reduction of cardiovascular risk. This study investigated the efficacy and safety of adding a new hypolipidemic agent, coenzyme A (CoA) to stable statin therapy in patients with mixed hyperlipidemia. METHODS: In this multi-center, 8-week, double-blind study, adults who had received ≥8 weeks of stable statin therapy and had hypertriglyceridemia (TG level at 2.3-6.5 mmol/L) were randomized to receive CoA 400 U/d or placebo plus stable dosage of statin. Efficacy was assessed by the changes in the levels and patterns of lipoproteins. Tolerability was assessed by the incidence and severity of adverse events (AEs). RESULTS: A total of 304 patients with mixed hyperlipidemia were randomized to receive CoA 400 U/d plus statin or placebo plus statin (n = 152, each group). After treatment for 8 weeks, the mean percent change in TG was significantly greater with CoA plus statin compared with placebo plus statin (-25.9% vs -4.9%, respectively; p = 0.0003). CoA plus statin was associated with significant reductions in TC (-9.1% vs -3.1%; p = 0.0033), LDL-C (-9.9% vs 0.1%; p = 0.003), and non- high-density lipoprotein cholesterol (-13.5% vs -5.7%; p = 0.0039). There was no significant difference in the frequency of AEs between groups. No serious AEs were considered treatment related. CONCLUSIONS: In these adult patients with persistent hypertriglyceridemia, CoA plus statin therapy improved TG and other lipoprotein parameters to a greater extent than statin alone and has no obviously adverse effect. TRIAL REGISTRATION: Current Controlled Trials ClinicalTrials.gov ID NCT01928342.

Preparation and characterization of pH sensitive comb-shaped chitosan material for the controlled release of coenzyme A.

A novel kind of pH sensitive comb-shaped copolymer P(CS-Ma-PEGMA) was synthesized with chitosan (CS), maleic anhydride (Ma) and Poly (ethylene glycol) methacrylate (PEGMA) by grafting and co-polymerization. The structure of P(CS-Ma-PEGMA) was characterized by FT-IR and (1)H-NMR, and it was found that PEGMA was grafted onto CS and PEGMAylated chitosan was soluble. The copolymer was subjected to coenzyme A adsorption study in order to assess its application in biomedical area. The factors affecting release behavior, such as concentration and pH were discussed in this paper. The higher concentration of the copolymer showed higher absorbance peak than the lower one. The pH of the solution also had significant impact on the release of coenzyme A, and the mechanism of adsorption was suggested. The results suggested that the novel copolymer could be used as drug delivery carrier.

Combined radiation-protective and radiation-sensitizing agents. IV: Measurement of intracellular protector concentrations.

Radiosensitization of hypoxic V79 Chinese hamster cells by 0.5 mM misonidazole at approximately 0-4 degrees C is substantially enhanced by pretreating the cells overnight with 0.1 mM buthionine sulfoximine, which lowers the cellular glutathione content to 5% of control values (from 4 mM to approximately 0.2 mM). The enhanced sensitization is reversed by concentrations of exogenous cysteine that are much lower (0.02 mM) than the original glutathione content. Reduced Co-enzyme A affords reversal of the enhancing effect at concentrations of about 1 mM. Sodium ascorbate gives no protection at all even at concentrations of 2 mM. The intracellular concentration of the reducing agents was measured using a spin-through oil technique. There was no diffusion of Co-A (MW greater than 750) or ascorbate (excluded by charge) into the cells. In contrast, cysteine was rapidly concentrated by factors of 4-10, even at the low temperatures used. Extracellular ascorbate's inability to radioprotect argues against electron transfer across the cell membrane as a mechanism for radioprotection. This mechanism could have explained the ability of exogenous thiols to radioprotect in former studies using glutathione, and in the present studies using Co-A. The potential of cysteine to be concentrated by cells poses a problem in the interpretation of "exogenous protection" by non-diffusing thiols, since trace contamination by cysteine could lead to the actual protection observed. Cysteine could also be formed by exchange reactions of exogenous thiols with the disulfide of cysteine, present in all media formulations.

Hepatic and cerebral coenzyme A contents after intravenous injection of coenzyme A in rats.

Hepatic CoA concentrations and contents were significantly higher in rats having received i.v. CoA injections that in control rats. Maximum hepatic CoA concentrations were found 0.5-1 h after injection. In rat brain, no increase in CoA concentration was detected after i.v. injection of CoA.